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  <script>
    // 1. 声明一个年龄变量
    // let age
    // // 2.赋值  =  赋值
    // age = 18
    // console.log(age)
    // 3. 声明的同时直接赋值
    // let age = 18
    //小案例
    let num = 20
    let uname = 'zym是帅哥'
    console.log(num)
    console.log(uname)

  </script>
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